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12:43 AM
Does mathematica have traditional programming datatypes? Like an int that is 32 bits and it will obey overflow rules?
I'm trying to simulate a PRNG implemented in a programming like c++ which is using unsigned ints!
 
 
2 hours later…
2:18 AM
@Adam can't you just do Mod 2^32?
 
Maybe, I'll try that out, ty you for the suggestion
 
 
5 hours later…
6:52 AM
@Adam there are machine integers on compiled functions, but they're not really there to be relied for modulo 2^32 arithmetic. You have to know their limitations, though, if you try to use them as arbitrary-lenght integers. And sure, they can be occasionally used for improved performance: mathematica.stackexchange.com/a/13708/3056 (very un-Mathematica though.)
 
7:13 AM
@Adam and speaking of modelling a specific PRNG on Mma, using Mod 2^32 almost definitely the way to go unless you're aiming for speed (I suppose not).
 
huhu is someone here ?
 
 
5 hours later…
11:54 AM
Someone is
 
@Rojo hi, someone
@Ajasja I'm going to update the Nelder-Mead answer at some point, BTW. I cleaned up the code a bit and fixed a bug with option handling. I also tried the so-called "adaptive" Nelder-Mead parameters of Gao and Han (here), which seem to be better in most cases for high-dimensional problems
 
That's Great! Although the current implementation is working very well for us, so no hurry.
@OleksandrR. I remember your comment a while ago about recommending Python for people that have no previous knowledge if either MMA or Python.
 
12:10 PM
Somethree now
 
I was part of a workshop on scientific programming and have come to realize that the advice is spot on.
Python + numpy + scipy (+ simpy) is a pretty powerful open source toolbox used by a large community.
 
@Ajasja I find that Python is pleasant to use and tolerant of a wide variety of programming styles without suffering horrible performance. I prefer to write functional code, but if people are used to a procedural or OO style, that's fine too.
NumPy's advanced indexing is also better than anything we have in Mma
 
I've never used python, but a friend of mine did all of his analysis and simulation work for his PhD in it.
 
@OleksandrR. Yup, so I have discovered:) Of course the licence is Pythons greatest advantage over MMA. Any scripts I run anybody can use as well.
And of course the availability of any number of external libraries.
 
12:31 PM
So if I export a function to C, and compile, will I be able to execute the program on a PC that doesnt have mathematica installed?
I guess not
but thats why Im asking
 
@CBenni For simple compiled functions it's actually possible to do.
Don't know the exact license terms for the runtime though.
@rcollyer My thesis still awaits (eagerly). But I'll keep it MMA for now. Too much already invested time to switch. And besides I still like MMA better.
Well gotta go. (thesis calling:)
 
@Ajasja mmhk... Apparently, my function is not easy enough...
CCodeGenerate::wmreq: The expression Runen requires Mathematica to be evaluated.   The function will be generated but can be expected to fail with a nonzero error code when executed. >>
Was to be expected
the function calls NMaxmimize :(
 
Hi everybody! I need some help, but it is probably not question worth... I have a couple of PDE (time and space/length) that are correctly managed by NDSolve, but to which I’m adding an ODE that “accumulates”, through time, a “parameter” coming from one of the boundaries of the PDE. The system is “linked” in the sense that the boundary varies with the accumulated value. I’ve tried a lot of stuff, but NDSolve keeps giving errors on the amount of parameters of the ODE, etc.
Turning it into a “PDE” didn’t help... I’m now thinking on managing the accumulation with the EvaluationmMonitoring, but it doesn’t sound right. Does someone has experience with this kind of scenario?
(I meant "not question worth" because I can't formulate it correctly...)
 
12:48 PM
I would like to help, but I dont know either
sorry about that ^.^
 
@CBenni Thanks anyway :)
 
YOu might just try to ask it on Mathematica.SE as a question
do your best to formulate it
add error messages
 
Did you understood my above description?
 
the people there have been very nice always ;)
I think I got the point, yes
havent done much with PDEs/ODEs in Mathematica tho
until now, its been mainly Integration and Maximization
 
I'm more on the system simulation needs... so, some ODE and PDE, but still a little amateur :)
 
1:17 PM
Question posted...
 
@P.Fonseca +1; I don't know the answer but it's an interesting question
 
1:34 PM
@OleksandrR. Thank you. It actually looks quite simple as a problem, and without it it seems difficult to manage simulation scenarios that go beyond the simple "one bar", "on pipe", etc. I'm almost certain that it is a question of correctly formulating the equations... I should also probably start working with Modelica...
 
 
1 hour later…
2:35 PM
Did anyone manage to get any graphical output when using the "EdgeLayout" suboption of GraphLayout?
The docs say,
> A graph layout is typically computed using several stages. With GraphLayout->{Subscript[s, 1]->Subscript[m, 1],[Ellipsis]}, stage Subscript[s, i] is handled by method Subscript[m, i].
So I did
Graph[{1 \[UndirectedEdge] 2, 2 \[UndirectedEdge] 3, 3 \[UndirectedEdge] 4}, GraphLayout -> {"VertexLayout" -> "CircularEmbedding", "EdgeLayout" -> "StraightLine"}]
And got
I simply can't seem to get any graphical output, regardless of the settings.
 
 
1 hour later…
4:20 PM
Does anybody know why ReplaceRepeated is not called ReplaceAllRepeated? Since there really is no ReplaceRepeated,i.e. , repeated application of Replace. One has to resort to FixedPoint. The M-language should be rewritten.
 
4:45 PM
@RolfMertig Correction: "Wolfram Language", as defined a week or so ago...
 
 
1 hour later…
6:09 PM
Does anyone now anything about this upcoming portal: Wolfram Community?
http://www.wolfram.com/community/?actkey=4807-1947-HH5UE9&version=9.0&os=Windows-x86-64&buildid=4055652&source=welcomescreen
Who could ask questions? Registered users? Who would answer? Only Mathematica personnel? Would this be a bit more open than e.g. bug reports to Technical Support?
 
@IstvánZachar Registered users can ask and answer. Users should answer, but personnel might also do that. However, I lost interest. I like this site more.
 
@RolfMertig So we are not out of business here, good to know : )
Care to share some experiences? Or is it confidential yet?
 
6:26 PM
@IstvánZachar Just try it out yourself: apply for the private beta and see. There are certainly very knowledgable people there and it does definitely have a use (e.g. suppose you don't want to let the world at large know what your problem is, or you don't want to follow the rules here.) Of course, WRI also has rules. Onle rule I like is that you have to sign up with your real name ... (while here one does not even know the mods names ...)
 
@RolfMertig Thanks for the information! I decided to wait for the public version.
 
@RolfMertig Oh please, "real names" can be easily faked... it doesn't take more than 5 mins to setup a pseudonym with a "nice" gmail account. Unless of course, WRI insists on seeing passport/driver's license verification (which can also be faked)
 
6:58 PM
@RolfMertig yeah I agree that it is strange that there is no Replace<notAll>Repeated... I think code will usually faster if you only want to replace expressions at top level if you define a function that calls itself iteratively. See the speed comparison in my answer here (between ggg2 and ReplaceRepeated for some rule) mathematica.stackexchange.com/a/21801/4330 But I do think that ReplaceRepeated will often be faster than alternatives with FixedPoint (or even Nest in case of gg2)
cya all
 
7:45 PM
@AndyRoss I was afraid something like that was going to happen when he was asking questions around here. Writing an in-depth review of Mathematica with just a few hours of practice simply won't work. His critique of TransformedDistribution is somewhat justified, though. It works for some basic combinations, but doesn't for many others.
 
8:27 PM
@rm-rf You need a Wolfram ID. Usually you don't fake that one, do you?
 
@SjoerdC.deVries I had seen the review but not read it closely. I didn't realize how negative it was. That is a shame!
I wonder if Leonid has seen it.
@IstvánZachar I've explored the Wolfram community a bit. One obvious difference is that it supports all Wolfram products. I can talk about WolframAlpha and people don't mind. :)
 
@MarkMcClure hopefully someone there might even be in a position to answer questions about W|A ;) I personally find it more trouble than it's worth because it's almost impossible to guess how it might interpret a query, so you waste your time trying different ways of phrasing the question before eventually giving up in disgust
 
@OleksandrR. I understand that. As a professor of mathematics, though, I tend to use it to show my students some fairly specific things.
And in that domain, it happens to work fairly well.
 
@RolfMertig All I'm saying is that there isn't nothing special about a Wolfram ID or the name one associates with it. I suspect many might use their actual IDs, but if someone wants to use a fake one, it's not hard :)
 
8:43 PM
Wow, I didn't know Homer Simpson used Mathematica!
Really??
 
in particular, trying to compose multiple queries usually ends up in utter frustration. It can tell you the caloric content of a certain amount of butter. It knows the volume of a cone. But try asking it for the caloric content of a cone of butter 13 furlongs in height and 1 foot base circumference...
@rm-rf it may make them suspicious (or even disallow you from using the service potentially?) if you have no licensed products
 
Quantity[32, "LargeCalories"]
 
@OleksandrR. If you use a university site license, it's not tied to your account...
 
@rm-rf not all site licences work like that
But if some do, okay.
 
8:46 PM
@MarkMcClure It's unfortunate that we have to restrict W|A questions, because I've seen you, Vitaliy and a few others extract a lot of mileage from it and do pretty neat stuff in your answers. However, a good number of the questions that we get (and have gotten) are ones wanting a quick and dirty solution to some math problem (and they don't know/want to do it in Mathematica)
 
@OleksandrR. But a query like this "life expectancy of 32 year old italian woman" works amazingly well
I didn't make this one up. I actually needed this somewhere in the past
 
Uh... We don't "have to" restrict W|A questions.
We just do.
I do understand the concern of loads of W|A questions, though.
 
@MarkMcClure fair enough :)
 
Ultimately, W|A is part of Mathematica. It just is. So there is a certain arbitrariness in the restriction.
 
13
Q: Other WRI product discussion?

insectWhat other Wolfram Research products are relevant to the scope of this site? Can we talk about Workbench issues - quite closely related to Mathematica, or something like the Wolfram Alpha API - less so. Where do we draw the line? (Or is it safe to ask about all WRI products?)

 
8:49 PM
@SjoerdC.deVries I'm aware of that, of course.
 
8
Q: Are questions about doing symbolic math in Wolfram Alpha on topic here?

Geoff OxberryI'm a mod at Computational Science SE. Sometimes, users ask questions on Computational Science about doing something in Wolfram Alpha. As far as I can tell, Wolfram Alpha uses Mathematica for its math engine. Are those questions on topic here? Note: I was made aware of Other WRI product discussi...

 
@MarkMcClure fwiw, I penned the opinion arguing for disallowing them, so I'm biased ;) You're welcome to dissent and change it (I agree that an all or nothing approach is not optimal, but there have been no other alternatives)
 
@MarkMcClure I know, you have answers there
 
Again, I'm aware of those all those discussions as well.
 
@SjoerdC.deVries some queries seem to be special-cased and readily understood. I guess these are the ones that relate very directly to data that it has available. Something I try from time to time is ask the mass of a certain shape of some material and it never gets it right for shapes other than a sphere or a cube
 
8:51 PM
But it is part of Mathematica. Why not disallow IsomorphicGraphQ?
 
"mass of a cone of manganese 1.7 metres height 2.6 metres base radius" fails completely, for instance, but if you want to know the mass of a manganese sphere, no problem.
 
@MarkMcClure W|A is not part of Mathematica, but Mathematica is part of W|A
 
IsomorphicGraphQ does use nauty, which I never cared for.
@SjoerdC.deVries Of course W|A is part of Mathematica.
 
@MarkMcClure Well, I specifically said that questions that are about interfacing W|A with mma are welcome... I just disagreed with allowing an easy backdoor to simple (otherwise off-topic) W|A questions just because they use the == option.
 
Just because a chess program is written in C doesn't make a question on that program valid in the C tag
 
8:54 PM
I know, I know and it's no real big deal.
I certainly don't want to fight about it!!
I do have one more little point that might take a minute to type.
 
@MarkMcClure No problem. It's good to bring it up now and then.
 
@MarkMcClure in the same sense that R is a part of Mathematica (well, a weaker sense, really, as it's an external service which we have no control over)... I doubt we're going to accept questions about R in the future
 
I'm not sure everyone understands how linked the products are and how much they influence one another. In Mathematica, the *Data functions, the predictive interface, the ease with which students can type in "=plot sin" - all these are there because of Alpha. Alpha has and is shaping Mathematica and folks here can see part of the future of Mathematica because of it. Because of this, I think the dismissive attitude that is often displayed is to the detriment of the group.
I should probably admit that the company does pay me to develop mathematical content for Alpha.
 
;-)
actually: $-)
 
But my opinion on that this is the Starship Enterprise computer was formed long before that!
OK, that's all.
Thanks for listening.
If you were. :)
 
9:00 PM
Youre welcome
 
$-)
@SjoerdC.deVries That review you referred to is a little disturbing.
I don't think you can ping Andy like that, though. He might not see your message.
 
@MarkMcClure Why not?
 
I seem to remember seeing @rm-rf mentioning that pinging in chat generally works only for mods.
Or if the user was recently here.
 
It's a reply on an earlier chat message that he ping-aimed at me
 
Hmm...
 
9:05 PM
@MarkMcClure If you reply by pressing the arrow at the end of the message, it pings the person
 
Ahh... Very cool - thanks!
 
@MarkMcClure Replies done that way start with an arrow. If you click on them, you get back to the message being replied to.
 
@SjoerdC.deVries I didn't even know that. I was just guessing that you were referring that Stat Blog review of Mathematica/R.
Right?
 
@MarkMcClure I feel it is missing the point a bit. And I don't quite know what is meant by "bugs and issues"--surely this author can't be regarding the fact that it takes a long time or is altogether impossible to find a closed form for certain convolutions as a bug, so what then?
 
@CBenni Well you could try to use Oleksanders Compiled Nealder-Mead here instead of NMinimize.
 
9:09 PM
What's his problem with the GUI?
@OleksandrR. !!
 
@MarkMcClure He's not very clear about that. It looks like he thinks it's a bit outdated.
 
I wonder if it's a windows thing about the GUI?
I don't know. I just know that I use Mac and have never had any huge issue with the GUI.
At least not until that damn predictive interface got in the way. :)
 
@SjoerdC.deVries to be fair it has not changed for a long time. But who cares. Who uses palettes anyway? They don't look any worse than you'd expect considering that they're meant to be a big panel of buttons
 
@OleksandrR. I use Szabolcs' palette, but that's about it, indeed.
 
I can't understand the meaning of this at all: "I’m going to bring back in Mathematica here.

Based on the GUI, I wonder… One more thing about the GUI, if you’re moving the palettes along it doesn’t do ghosting, so it pops back in."
 
9:15 PM
I'm looking at it again. He's got an example where he uses nested For loops for a speed comparison.
I think it's pretty obvious that he's not a native speaker of Mathematica.
 
Alex Miller on March 27, 2013

Our guest this week (after she joins a bit late) is Zuly Gonzalez – Stack Exchange moderator and power user.  As usual, we also have David Fullerton, Jay Hanlon, Joel Spolsky and (Fake) Producer Alex!

Things are a mess over here, not just because we have to remember to stop masticating long enough to talk about podcast things. We’re moving offices! The office is full of crates into which we have to pack all our stuff before we move.

The new office is going to be awesome. It has hexagonal offices, and we don’t remember if we’ve talked about this before. …

 
@MarkMcClure I think mentioning this is probably reasonable. But nobody is going to buy Mathematica just so they can write their nested For loops, so in context I can't really see what it's intended to demonstrate
 
I think it's just a speed comparison.
 
Okay, I have to go for a while. Back later.
 
Ciao
 
9:21 PM
It seems like this person is trying to use notebooks like scripts in other languages — i.e., a script for each little thing and a master function that calls them/passes parameters, etc. It might be a good opportunity to write a detailed post on how to efficiently structure and use a single notebook
 
How, were you able to glean that from the post??
 
@MarkMcClure Oh, did I misread the question?
Let me read it again...
 
I honestly don't know!!
I think I see what you're saying. He thinks it's a good idea to use notebooks to separate data, code, and other stuff.
 
He probably doesn't know about sections/initialization cells, and must be writing his data/functions sequentially (heavy scrolling). He's afraid of making a large notebook because he doesn't know how to fold... At least, that's what I got out of it
 
I think you could be right.
I tend to avoid questions where I need to guess.
Too many times I've created an example illustrating what I thought they were working on only to hear, no that's not what I meant.
 
9:30 PM
@MarkMcClure I agree, those can be frustrating. Perhaps it's better to ask first in a comment
 
It could be that he has genuinely huge data, large enough to affect the performance of his notebook.
In that case, I'd recommend placing it in a .m file, I guess.
 
Shouldn't he be importing it then, instead of copy-pasting in a cell?
 
Well, I asked something.
 
10:11 PM
I know I owe some replies on the remove duplicates question, and also that I said some things that are incorrect. I beg just a little more patience.
 

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